DNO connections. Great Britain
What does a three phase supply cost?
There is no published price, and anyone quoting you one from a web page has not seen your street. The supply work belongs to your distribution network operator, which quotes it under a connection charging methodology that Ofgem approves but does not price line by line. Ofgem's own summary of what the quote depends on is short: how much work they have to do and how long it will take, your location, and how much energy you will need supplying to the property. Tell us about the site and contractors will price the job.
3 months
the maximum time your network operator has to give you terms for a connection, including how it works out the charge
Two parts
quotes split into contestable work, which another approved contractor can carry out, and non-contestable work, which only the network operator can do
Paid up front
Ofgem states you will probably need to pay for the connection in advance of the work
What happens next
- Tell us about the property, the load and the distance to the network. Two minutes, no account.
- We pass your details to electrical contractors and connection providers covering your postcode, and to no one else.
- They come back with a price for the work they can do, and handle the network operator application with you. Compare, choose, or walk away.
Three Phase Cost is a free introduction service operated by Ellul Solutions Ltd; we pass your details to electrical contractors and connection providers who quote you directly. We may receive a fee from providers; you pay nothing and are under no obligation. We are not electricians, a network operator or an independent connection provider, and nothing here is design or legal advice. We publish no price range because connection charges are set by each network operator's own approved methodology and by site conditions we cannot see, so the quotation you receive is the only figure that means anything.
What sets the price of a three phase supply upgrade, 2026
Last updated
A three phase upgrade is two jobs with one outcome. The network operator brings the supply to the property and charges for it under its own approved methodology; your electrician deals with everything from the meter position inwards. This table sets out what moves each part of the price, and the question to ask so that two quotes describe the same job.
This is a cost-driver table rather than a price list. Connection charges are calculated under each network operator's connection charging methodology, which Ofgem approves without approving individual charges, and the figure for any given property depends on distance, ground conditions, load and whether network reinforcement is triggered. No price range is published here because we cannot evidence one that would hold across those variables, and a national average would be at its least accurate for the properties that most need an answer. The rows describing the quote process, the contestable split, advance payment and the three-month terms deadline are taken from Ofgem's guidance on getting a gas or electricity connection, read on the updated date above. Prices for your own property come from the network operator and the contractors, through the form above.
| Cost driver | Why it moves the price | What to ask for |
|---|---|---|
| Distance to a suitable network cable | The single biggest variable in most quotes. Bringing three phases from a cable at the boundary is a different job from trenching a couple of hundred metres up a farm track, and the price scales with the metres of cable and excavation rather than with the kilowatts | The route the operator has assumed, in metres, and what it costs per metre in the quote breakdown |
| Whether reinforcement or a new substation is needed | If the local network cannot carry the new load, the answer is not a bigger cable to your property but work upstream: a transformer, a substation or reinforcement of the existing network. This is the step change that turns a modest quote into a large one | Whether the quote includes any reinforcement, and what the position would be at a lower requested capacity |
| The load you ask for | You are quoted against the capacity you request, and the capacity you request determines whether the existing network can serve you. Asking for headroom you will never use can trigger reinforcement; asking for too little means a second application later | A load assessment behind the requested capacity, with diversity applied, rather than a total of every nameplate rating on site |
| Ofgem's three stated quote factors | Ofgem summarises what a connection quotation depends on as: how much work the operator has to do and how long it will take, your location, and how much energy you will need supplying to the property. Every other row here is a way of expressing one of those three | The quotation broken down against those factors, and the connection charging methodology it was calculated under |
| Contestable and non-contestable split | Ofgem notes that a registered electrician or engineer can do some parts of connection work, called contestable work, and that this can help bring down costs. The rest is non-contestable and only the network operator can do it. The split changes both the price and who you are contracting with | Quotations that break the work into contestable and non-contestable costs, which is exactly what Ofgem advises asking for |
| Excavation, surfaces and reinstatement | Digging through a lawn is not digging through a block-paved drive, an adopted footway or a carriageway. Road crossings, traffic management and reinstatement to the highway authority's specification sit inside the connection price and are often the reason two neighbouring properties differ | What surfaces the price assumes, what standard of reinstatement is included, and who is responsible if the surface is different once opened |
| Domestic or commercial site | The engineering is similar; the surrounding requirements are not. Commercial sites more often need metering arrangements, a substation or switchroom, and access and safety provisions that a house does not, and the internal distribution work is a larger share of the total | Whether the price covers only the incoming supply, or also the switchgear, metering position and distribution the site needs |
| Everything from the meter inwards | The network operator's job stops at the supply. Main switchgear, a three phase distribution board, earthing and bonding, submains, and moving or re-siting the intake are your electrician's work, quoted separately, and it is a real cost rather than a rounding error | A separate itemised quote for the internal works, and confirmation of who arranges the meter with your energy supplier |
| Programme and sequencing | Ofgem requires your network operator to give you terms for a connection within three months, including information on how it works out the connection charge, and states that you will probably need to pay for the connection in advance. Scheduling the physical work is separate again, and other trades usually wait on it | The date terms will be issued, the payment milestones, and the earliest realistic date for the site work |
| Meter and supplier arrangements | Ofgem advises choosing an energy supplier to get a meter installed and arranging this at the same time as the connection to avoid delays, and warns that it is illegal to move your own energy meter. A completed connection with no meter is not a working supply | Who is instructing the supplier for the meter, and when, relative to the connection date |
- There is no national price for a three phase supply upgrade: connection charges are calculated under each network operator's connection charging methodology, which Ofgem approves without approving individual charges.
- Ofgem states that a connection quotation depends on how much work the operator has to do and how long it will take, your location, and how much energy you will need supplying to the property.
- Your network operator must give you terms for an energy connection within three months, including information on how it works out the connection charge, and must compensate you if it fails to meet the guaranteed standards of performance (Ofgem).
- Ofgem advises asking for quotations that break connection work into contestable and non-contestable costs, because a registered electrician or engineer can carry out the contestable part and that can bring the price down.
Cite this page
“What sets the price of a three phase supply upgrade, 2026”, Three Phase Cost, https://threephasecost.co.uk/ (updated 2026-08-14). This is a cost-driver table rather than a price list. Connection charges are calculated under each network operator's connection charging methodology, which Ofgem approves without approving individual charges, and the figure for any given property depends on distance, ground conditions, load and whether network reinforcement is triggered. No price range is published here because we cannot evidence one that would hold across those variables, and a national average would be at its least accurate for the properties that most need an answer. The rows describing the quote process, the contestable split, advance payment and the three-month terms deadline are taken from Ofgem's guidance on getting a gas or electricity connection, read on the updated date above. Prices for your own property come from the network operator and the contractors, through the form above.
Read next
Every figure sourced and dated.
Three phase upgrade: who does the work, DNO or electrician?
The network operator owns the supply up to the meter position. Your electrician owns everything after it. Getting the split wrong is what stalls these projects.
Single phase or three phase: do you actually need the upgrade?
Three phase solves a capacity problem and a motor problem. If you have neither, a larger single phase fuse or load management is usually cheaper and quicker.
Three phase for EV charging and heat pumps: when it is needed
Electrification is the main reason people ask for three phase now. What triggers a genuine need, and how to sequence the application so the project does not stall.
Frequently asked
How much does it cost to upgrade to a three phase supply?
There is no published price. The connection is quoted by your distribution network operator under its connection charging methodology, and Ofgem states that the quotation depends on how much work they have to do and how long it will take, your location, and how much energy you will need supplying to the property. Distance to the network and whether reinforcement or a new substation is needed move it most.
Who quotes for a three phase upgrade?
The distribution network operator for your area quotes the supply work, and Ofgem's guidance is to contact them to get electricity installed or alter a connection. Your electrician quotes separately for everything from the meter position inwards. Some connection work is contestable and can be carried out by a registered electrician or an independent provider.
What is contestable and non-contestable work?
Ofgem describes contestable work as the parts of a connection that a registered gas engineer or electrician can do, which can help bring down costs, with the network operator possibly needing to agree or inspect it. Non-contestable work can only be done by the network operator. Ofgem advises asking for quotations that break the two apart.
Do I have to pay for a connection in advance?
Ofgem states that you will probably need to pay for the connection in advance. It also requires network operators to give you terms for a connection within three months, including information on how the connection charge is worked out, and to compensate you where they fail to meet the guaranteed standards of performance.
Does Ofgem approve the price my network operator charges?
Ofgem approves the connection charging methodology, which you can find on your network operator's website, but states directly that it does not approve any individual charges. That is why quotes for similar work differ between operators and between sites.
Can I dispute a connection quote?
Ofgem can resolve disputes with network operators in some situations and publishes guidance on the determination of disputes over use of system or connection to energy networks. Start with the operator's own complaints process, and keep the quotation breakdown and correspondence.